Overview and Rationale for the PURE Study

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Overview and Rationale for the PURE Study
Dubai, UAE January 6, 7 2006
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Life Enhancing Average Life Expectancy at Birth
Economist, Nov 2001
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EPIDEMIOLOGIC TRANSITION OF CARDIOVASCULAR
DISEASES
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Contribution of NCD to the Global Mortality and
GBD in 1998, in LIC MIC Countries
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Schema of Relative CVD Rates in Different
Societies Based on Early vs Late Industrialization
India/China
Stage of EPI Transition
N.Am/W. Eur
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REASONS FOR THE GLOBAL INCREASE IN CVD

• Decrease in childhood and infectious diseases ?
  more middle age older people
• Increased tobacco used
• Urbanization
• ? phys activity during daily life (e.g.
  automation, cars, etc.)
• ? energy consumption
• ? fat consumption
• ? psychosocial stress

Increase in Wt/Obesity
Dyslipidemia, Dysglycemia, ? BP
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Percent of Population Living in Urban Settings
1970-2025
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Risk of AMI associated with Risk Factors in the
Overall Population
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Population Attributable Risk by Region and Overall
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Population Attributable Risk by Region and Overall
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A Societal Pathophysiologic Pathway for COR HT DIS
RURAL LIFESTYLE
- -

• Consumption of energy rich food
• Sedentariness (in usual daily activities)
• Psychosocial factors

• Modifying influences
• Healthcare
• Genes
• Knowledge Attitudes

• Proximal Determinants
• of Behaviour
• urban structure
• mechanization
• Food Tobacco policy
• Cultural attitudes
• Social/Education
• Global influences

Clinical Events
Obesity and other risk factors

URBAN LIFESTYLE
Yusuf et al. Circ 2001
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What is a normal BMI?
Normal derived from modern day Western countries
may not be appropriate .

• Median BMI of newborns 13(USA)
• Median BMI of 16 yr olds16(USA)
• Median BMI of 20 yr olds20(USA)
• Median BMI of adult males in the 190021(USA)
• Median BMI of rural B Lore 19.5(India)
• Median BMI in Anquing study 19 (China)
• So, why is a BMI of 25 considered to be normal?

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INTERHEART Apolipoprotein B/A-1 and MI
Deciles 1 2 3
4 5 6 7
8 9 10 Cont
1210 1206 1208 1207
1210 1209 1207 1208 1208
1209 Cases 435 496
610 720 790 893 1063
1196 1366 1757 Median
0.43 0.53 0.60 0.66 0.72
0.78 0.85 0.93 1.04
1.28
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Conceptual issues in examining regional
variations in disease

• 1. State of development of the country or region
  in relation to the epidemiological transition.
• 2. Level of urbanization.
• 3. Variations in ethnicity (cultural and
  biological)
• 4. Socioeconomic status, lifestyle (local level
  variations)

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Four major transitions associated with
urbanization (1)

• Mechanization, motorization, energy saving
  devices
• ? changing economic structure, with increasing
  importance of non-agricultural sectors
• increasing investment in telecommunications,
  transportation and electrical infrastructure
• Declining physical activity
• More sedentary modes of transportation
• Changing work structure, increased mechanization
  leads to less energy expenditure at work and home

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Four major transitions associated with
urbanization (2)

• Changing dietary patterns
• Shift in food production, distribution,
  availability and costs
• Higher energy, fat, animal protein, refined and
  processed food intakes, lower intake of
  traditional grains, fruits, vegetables, greater
  variety
• Changing stressors, quality of social support
• Fragmentation of traditional family structure
• Increased job stress
• Absence of community support systems (social
  capacity)

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Urban Versus Rural Environments Not dichotomous
or unchanging

• Marked variations within urban and rural
  environments, but also between urban and rural
  environments within a region
• Directions of differences in social, cultural and
  biologic differences between urban and rural
  environments vary between HIC, MIC and LIC (e.g.
  CVD less in rural areas of LIC, but more in some
  urban areas of HIC)
• Urban and rural environments themselves evolve
  over time
• Rural ? urban through economic developments and
  expansion of cities to include neighbouring rural
  communities
• Urban ? favourable or unfavourable environments
• THE ABOVE CHANGES ARE ASSOICATED WITH MARKED
  SOCIETAL AND LIFESTYLE CHANGES

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TWO FUNDAMENTAL TENETS

• Obesity, Diabetes and CVD are Normal Biologic
  Responses to Abnormal Environments
• Biologic factors are generally deterministic (and
  hence the intervention strategies are more
  generalizable). Societal factors have a more
  contextual impact ( and hence the approaches to
  societal interventions may be more variable.

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Basis For PURE

• CVD burden is increasing globally and 80 occurs
  in L MIC
• Increasing in LMIC
• Decreasing in HIC
• Epidemiologic transition has been hypothesized as
  the cause, but has not been studied
• Key INTERHEART Study Observations
• gt90 of AMI globally explained by 9 modifiable
  risk factors
• Similarity of impact in all regions and ethnic
  groups

So, What Causes These Risk Factors?
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The Prospective Urban and Rural Epidemiologic
(PURE) study
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3 interrelated levels of questions

• Societal influences on health behaviours ,risk
  factors and chronic diseases.
• Differences in health behaviours, risk factors
  and disease between urban and rural settingsand
  their variations in a range of countries at
  various levels of economic advancement.
• Relationship of societal and individual level
  factors on disease rates.

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Hypothesis

• Maladaptation to urbanization is the proximate
  cause of obesity, which leads to elevated risk
  factors (dyslipidemia, dysglycemia,
  hypertension). The risk factors interact with
  genetic and psychosocial factors resulting in
  increased CVD.

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Scope

• Primary area of interest
• CVD, Diabetes and Obesity
• Secondary goals (high disease burden)
• Other chronic disease e.g. common cancers
• Infectious diseases e.g. TB
• Respiratory diseases e.g. COPD, asthma
• Injury and disability
• Depression

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Objectives - Baseline

• To Examine
• Urban-rural differences in
• Levels of proximal exposures (built
  environment,mechanization,activity, community
  structure, urbanization, diet, food and tobacco
  policies and prices)
• Prevalence of risk factors (conventional and
  emerging)
• Prevalence of disease.
• 2. Clustering of the above within
  households,within communities and within countries

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Objectives Longitudinal study

• To determine
• whether changes in urbanization are associated
  with variations in lifestyles and risk factors
• how changes in individual (lifestyle) are
  affected by changes in community level factors
  (eg. mechanization, access to health care) are
  related to variations in risk factors and disease
  rates/disability
• how the above vary in different regions of a
  country or across countries
• predictors of disease.
• to track risk factor changes and disease rates
  over time in the communities studied.

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Current Status of PURE

• Countries actively recruiting
• India 22,000 subjects from 5 centres
• South Africa Over 2000 individuals from one
  center
• China 11,000 subjects from 10 locations.
• Begun recruiting
• Colombia , Sweden and UAE
• Ready to start
• Brazil, Argentina,Iran, Sweden,Canada,Chile
  ,Zimbabwe.
• Other interested countries
• ?Thailand, ?Russia,Tanzania, Poland.

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PURE Timeline

• Initial conceptualization of project July
  2000
• Data collection starts in Jan 2001
• Bangalore and Palamaner
• PUREIndia Mtg Kerala, Rajasthan June 2001
• Trivandrum join the study
• 1st PURE International SC Meeting May 2002
• Sydney, Australia
• Chandigarh identified as 5th site within
  India June 2002

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PURE Timeline

• 2nd PURE International SC Meeting April 2003
• Marbella, Spain
• Setup and Recruitment for an international August
  2003
• PURE pilot in 11 countries outside of India
• 3rd PURE International SC Meeting December 2003
• New Delhi, India
• PURE India Meeting December 2004
• Bangalore, India

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PURE Timeline

• PURE India Meeting December 2004
• Bangalore, India
• PURE South Africa Meeting February 2005
• Potchefstroom, South Africa
• PURE Zimbabwe Meeting February 2005
• Harare, Zimbabwe
• PURE China Meeting March 2005
• Beijing, China

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PURE Pilot StudyDietary Intakes
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PURE Pilot StudyLevel of Mechanisation
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PURE Pilot StudyPhysical activity
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PURE Pilot StudyAnthropometry
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PURE Pilot StudyDisease Prevalence